1. Field of the Invention
The present invention relates to a processed cranberry product which is so prepared that the fruit becomes soft but the original cranberry form is maintained, and to a process for preparing such a processed cranberry product.
2. Description of the Related Art
Cranberries are the fruits of the cranberry bush, which is a plant belonging to the heath family and is grown in bogs in the Northern Hemisphere from the frigid zone to the temperate zone. They are in the form of a ball having a diameter of 15 to 20 mm, the surface of which is covered with an ekocarp, which is a waxy skin similar to that of the Chinese lantern plant. As cranberries are strongly acidic, fresh cranberries are not suitable for eating; they are squeezed to provide cranberry juice, cocked with sugar to provide a preserve, or sweetened then dried to provide dried cranberries which are eaten as dried fruit.
Since cranberries are covered with a relatively strong skin, and the ovary of the fruit is divided into three chambers by the dissepiment, when heated, air in the chamber of the ovary may expand and rupture the exocarp, or the sarcocarp may flow out to damage the appearance of the resulting product. Therefore it is difficult to obtain a product having a good appearance. Accordingly, no processed cranberry products are known in which the processed cranberries remain in the spherical form.
Accordingly, it is an object of the present invention to provide a novel processed cranberry product maintaining a spherical form from cranberries having the above-mentioned nature and properties. Another object of the present invention is to provide a cranberry processing method which is suitable for preparing such a novel processed cranberry product.
A feature of the processed cranberry product according to the present invention is that softened and sweetened sarcocarp (fruit flesh) is maintained in the spherical skin of the cranberries.
The above-mentioned processed cranberry product can be advantageously produced by a processed cranberry product preparing method comprising puncturing the skin of frozen cranberries such that a plurality of holes are provided, submerging the punctured cranberries in a sugar solution having a sugar content of 45 to 65 Brix degrees, and heating the cranberries until the sarcocarp is softened.
In the processing of the cranberries, the size of the puncture needle is preferably from 0.3 to 0.8 mm, and the sugar solution is preferably an aqueous solution of honey.
It is desirable that ripe and solid cranberries are used as the raw fruits for the process according to the present invention, since unripened cranberries have weak skins and tend to collapse during cooking. Overripe fruits may also be used in some cases.
Cranberries are washed with water if necessary to remove extraneous material, then are frozen in a freezer etc. The freezing treatment is essential for smoothly carrying out the following puncturing treatment, and freezing of the cranberries to a sufficiently low temperature is preferable.
An example of an apparatus for puncturing the frozen cranberries may comprise a processing plate in the form of, for example, a frog on which many puncture needles are planted at appropriate intervals, and a pressure belt, which may be made of, for example, rubber, the plate and the belt being positioned vertically and facing each other at such an interval that allows the cranberries to be pinched. In such an apparatus, fruits supplied from above between the processing plate and the pressure belt are rotated by the pressure belt and sent downward. Thereby the whole periphery of the skin of the fruit is nearly uniformly punctured several times. The puncturing apparatus for the fruits is not limited to this apparatus, and any apparatus having a similar function can be employed as well.
The cranberries punctured by the use of the puncturing apparatus as described above can pass very easily through the apparatus when they are frozen, however if they are thawed on the way, the fruits punctured by the needles may not roll but may collapse or clog the apparatus to stop the operation. Therefore, the fruits are frozen to a sufficiently low temperature as described above, so that they will not be thawed after being supplied to the puncturing apparatus until the puncturing process is completed.
The punctured cranberries are put into a previously prepared sugar solution having a sugar content of 45 to 65 Brix degrees, preferably at the ratio of the cranberries to the solution of almost 1:1 by weight, and gradually heated to around 65xc2x0 C. When the temperature rising rate is too large, the exchange between air in the fruit and the sugar solution does not take place sufficiently, and an efficient recovery of the processed cranberry product which is spherical and soft becomes difficult. Therefore, it is desirable to take at least 10 minutes for the temperature of the cranberries to rise from the normal temperature to reach 65xc2x0 C.
Additionally, the sugar solution used therefor must have a sugar content of 45 to 65 Brix degrees for producing a processed cranberry product having a spherical form and balanced acidity and sweetness. When a sugar solution having a sugar content below 40 Brix degrees is employed, too much solution enters the fruit to cause swelling of the cranberries which may result in rupturing or collapsing of the fruits. On the other hand, a sugar solution having a sugar content over 65 Brix degrees may draw out the juice from the fruits to shrivel the cranberries and the balanced taste is degraded as well.
Preferable examples of the sugar solution used in the present invention include, but are not limited to, aqueous solutions containing glucose, fructose, sucrose and the like as the main component, and any other appropriate sugar solution can be employed as well. A honey solution, for example, can provide a desirable processed cranberry product having a good flavor.
After the cranberries submerged in a sugar solution having a sugar content of 45 to 65 Brix degrees are slowly heated to 65xc2x0 C., they can be cooked at a temperature of 70xc2x0 C. or higher if necessary, or they can be heated until the liquid boils, if so desired. Through such a sugaring process, a tasty processed cranberry product having the spherical skin filled with a soft and sweetened sarcocarp can be produced.
As described above, according to the present invention, a novel processed cranberry product having a beautiful color and form, which is filled with a soft and tasty sweetened sarcocarp, can be placed on the market by puncturing the frozen cranberry skin, thereby preventing the swelling of the sarcocarp and the rupturing of the cranberries during the sweetening process, as well as facilitating the migration of the sugar into the sarcocarp, and further by limiting the sugar content of the sugar solution used for the process within a range from 45 to 65 degrees, thereby maintaining the spherical form of the skin, and providing a well-balanced sweet-sour taste.